The present invention relates generally to arrangements and methods for treating a subject. In particular, the present invention is directed to arrangements and methods are provides which simulate an application of amount of energy upon a target area, determine whether an equivalent uniform dose (xe2x80x9cEUDxe2x80x9d) associated with a portion of the energy received by a first structure is greater than a dose tolerance of the first structure, and/or determine whether an EUD associated with a portion of the energy received by a second structure is greater than a dose tolerance of the second structure.
The present invention relates generally to arrangements and methods for treating a subject. In particular, the present invention is directed to an arrangement and method in which a computer system executes a computer program, and determines whether an equivalent uniform dose associated with a particular dose distribution is greater than a dose tolerance associated with a first structure within the subject and/or a dose tolerance associated with a second structure within the subject.
Chemotherapy, surgery, and radiotherapy are three of the most prominent methods of treating cancer and/or tumors in a subject. Radiotherapy is particularly useful when the cancer is restricted to a primary target area (e.g., when there are no metastases), and/or when the target area may not accessed via surgery. Certain conventional radiation therapy treatment plans are iterative forward processes, in which initial parameters (e.g., radiation beam intensity and radiation beam direction) are selected to produce an initial spatial dose distribution (e.g., radiation beam intensity and/or radiation beam direction may determine the spatial dose distribution), and the initial parameters are successively altered until a desired spatial dose distribution is achieved. Other conventional radiation therapy treatment plans are inverse processes which begin with the desired spatial dose distribution, and operate backwards to determine the treatment parameters that will come the closest to achieving the desired spatial dose distribution. The process for selecting the desired spatial dose distribution involves balancing of conflicting goals. Specifically, increasing an intensity of a radiation dose increases the likelihood that the target area will be effectively treated. Nevertheless, increasing the intensity of the radiation dose also increases the likelihood that structures (e.g., organs and/or tissue) within the subject which are outside the target area may be damaged during treatment. As such, the process of selecting the desired spatial dose distribution involves balancing a desire to effectively treat the target area with a preference not to damage the structures outside the target area.
The structures within the subject may be either parallel-type structures or serial-type structures. Parallel-type structures are those structures in which a function of the structure may be preserved even when a portion of the structure is damaged. In contrast, serial-type structures are those structures in which the function of the structure may not be preserved when any portion of the structure is damaged. For example, a lung may be a parallel-type structure, and a spinal cord may be a serial-type structure.
In radiation therapy treatment plans, and particularly in computer aided treatment plans, it may be desirable to characterize an effect of the spatial dose distribution as a single number. One conventional method for characterizing the effect of the spatial dose distribution as a single number is an equivalent uniform dose (xe2x80x9cEUDxe2x80x9d). The EUD may be defined as a uniform dose distribution that would lead to the same effect as a given non-uniform, spatial dose distribution. Further, each structure within the subject may have an associated EUD tolerance, and there are numerous conventional methods for determining the EUD tolerance associated with a particular structure within the subject. When an EUD associated with an amount of radiation received by a particular structure is less than or equal to an EUD tolerance associated with the particular structure, the function of the particular structure would likely be preserved. Nevertheless, when the EUD associated with the amount of radiation received by the particular structure is greater than the EUD tolerance associated with the particular structure, the function of the particular structure may not be preserved.
In conventional radiation therapy treatment plans employing EUD, the actual EUD tolerances of those structures which a doctor determines can be adversely affected by radiation transmitted to the target area are used to determine a single, combined EUD tolerance value associated with these structures. Nevertheless, in such conventional radiation therapy treatment plans, the actual EUD tolerance of each structure within the subject may be different than the combined EUD tolerance, e.g., the EUD tolerance of a particular-structure within the subject may be less than or equal to the combined EUD tolerance.
In these conventional systems, a physician may select a desired EUD associated with radiation to be received by the target area, and a computer system may determine the amount of radiation for transmission to the target area based on the desired EUD, e.g., an intensity and/or a direction of the radiation beams which will achieve the desired EUD in the target area. Moreover, if the combined EUD is greater than or equal to an EUD associated with a portion of the desired amount of radiation which a structure would receive, the desired amount of radiation is transmitted to the target area. The determination of whether to transmit the desired amount of radiation to the target area is made independent of the actual EUD tolerance associated with the structure. Nevertheless, if the desired amount of radiation is transmitted to the target area, and the actual EUD tolerance associated with the structure is less than the EUD associated with the portion of the radiation which the structure receives, the function of the particular structure may not necessary be preserved.
Therefore, a need has arisen to provide arrangements and methods for treating a subject which overcome the above-described and other shortcomings of the related art.
One of the advantages of the present invention is that arrangements and methods are provided in which an application of a particular amount of energy (e.g., iteratively simulates different beams of radiation beams having varying intensities and/or direction) upon a target area or target areas (e.g., a cancer or a tumor) within a subject is simulated. For example, when energy (e.g., radiation) is transmitted to the target area, a portion of the energy may be received by structures (e.g., organs or parts thereof) within the subject which are outside the target area. When the simulation indicates that an equivalent uniform dose (xe2x80x9cEUDxe2x80x9d) associated with a portion of the energy received by a particular structure is greater than a dose tolerance associated with the particular structure, a function of the particular structure may not be preserved.
Consequently, when simulating the application of the amount of energy upon the target area, it is possible to determine whether the EUD associated with the portion of the energy which the particular structure would receive is greater than the dose tolerance of the particular structure. This individual determination can be made for any number of structures within the subject. If the EUD associated with the portion of the energy which the particular structure would receive is greater than the dose tolerance of the particular structure, an application of a further amount of energy, e.g., a lesser amount of energy, can be simulated in which an intensity of at least some of the radiation beams are reduced. For example, the computer system can use a projection onto convex sets procedure to determine an appropriate further amount of energy. The simulation can continue until an optimum amount of energy to be applied to the target area, e.g., the greatest amount of energy is determined, which can be transmitted to the target area while also preserving the function of each of the structures. For example, the energy may include a plurality of radiation beams, and each of the radiation beams may have an associated intensity. Further, some of the radiation beams may only affect the particular structure, and some of the radiation beams may only affect a different structure, such that the intensity of each of the radiation beams can be adjusted based on EUD tolerance of the structure which they affect.
According to an exemplary embodiment of the present invention, an arrangement and method simulate an application of a particular amount of energy (e.g., radiation having a plurality of radiation beams) upon a target area or target areas (e.g., a cancer or a tumor) within a subject, in which a first structure (e.g., an organ) within the subject receives a first portion of the particular amount of energy, and a second structure within the subject receives a second portion of the particular amount of energy. A determination can also be made as to whether a first equivalent uniform dose (xe2x80x9cEUDxe2x80x9d) associated with the first portion of the particular amount of energy received by the first structure is greater than a first dose tolerance (e.g., EUD tolerance) associated with the first structure. It can also be determined as to whether a second EUD associated with the second portion of the particular amount of energy received by the second structure is greater than a second dose tolerance associated with the second structure.
In another exemplary embodiment, an application of a further amount of energy (e.g., an amount of energy which is different than the particular amount of energy, having different radiation beam intensities and/or directions) is simulated upon the target area, in which the first structure receives a first portion of the further amount of energy, and the second structure receives a second portion of the further amount of energy. It is also determined as to whether a third EUD associated with the first portion of the further amount of energy received by the first structure is greater than the first dose tolerance, and whether a fourth EUD associated with the second portion of the further amount of energy received by the second structure is greater than the second dose tolerance. For example, a projection onto convex sets (xe2x80x9cPOCSxe2x80x9d) procedure can be used to determine an appropriate further amount of energy to be applied to the target area during the simulation.
Moreover, an intensity of the further amount of energy relative to an intensity of the particular amount of energy may depend on the above-described determinations. For example, an intensity of the first portion of the further amount of energy may be less than an intensity of the first portion of the particular amount of energy when the first EUD is greater than the first EUD tolerance by a predetermined amount. Similarly, an intensity of the second portion of the further amount of energy can be less than an intensity of the second portion of the particular amount of energy when the second EUD is greater than the second EUD tolerance by the predetermined amount. In contrast, the intensity of the first portion of the further amount of energy may be greater than the intensity of the first portion of the particular amount of energy when the first EUD is less than the first EUD tolerance by the predetermined amount. Similarly, the intensity of the second portion of the further amount of energy can be greater than the intensity of the second portion of the particular amount of energy when the second EUD is less than the second EUD tolerance by the predetermined amount. Moreover, the intensity of the first portion of the further amount of energy may be equal to the intensity of the first portion of the particular amount of energy when the first EUD is within the predetermined range of the first EUD tolerance. Similarly, the intensity of the second portion of the further amount of energy can be equal to the intensity of the second portion of the particular amount of energy when the second EUD is within the predetermined range of the second EUD tolerance.
In yet another exemplary embodiment of the present invention, data is forwarded to, e.g., to a distribution assembly. This data is associated with a resultant amount of energy for an application to the target area when at least one of the first EUD and the third EUD is within a predetermined range of the first EUD tolerance, and at least one of the second EUD and the fourth EUD is within the predetermined range of the second EUD tolerance. Moreover, the distribution assembly may transmit the resultant amount of energy to the target area. For example, the energy can include radiation, and the radiation can include at least one first radiation beam and at least one second radiation beam. Further, an intensity of the at least one first radiation beam may be associated with at least one of the first EUD and the third EUD, and an intensity of the at least one second radiation beam can be associated with at least one of the second EUD and the fourth EUD.